The present invention relates generally to fuel transfer systems, and more particularly to a hydrogen fueling station for vehicles.
Internal combustion engines are the power source for almost all motorized wheeled vehicles today. Due to the finite supply of fossil fuels and the adverse environmental effects associated with burning these fuels, vehicles are now being developed that are powered by alternative xe2x80x9cenvironmentally friendlyxe2x80x9d fuels like hydrogen. Such vehicles may be powered by fuel cells, which produce electric power by electrochemically reacting hydrogen fuel with an oxidant such as air. Other hydrogen-powered vehicles include those that combust hydrogen. Supplying hydrogen, especially gaseous hydrogen, to fuel cell vehicles (FCV) and other hydrogen-powered vehicles, presents certain challenges not encountered when fueling vehicles with conventional liquid petroleum-based fuels like gasoline.
Given that the hydrogen-powered vehicle industry is still in its infancy, there is no known hydrogen fueling infrastructure that has been developed to widely supply hydrogen fuel to FCVs and other hydrogen-powered vehicles. In the absence of such an infrastructure, the first FCVs have been built with on-board reformers, which are devices that extract hydrogen from hydrogen-containing fuels such as alcohols or specially-formulated petroleum. While reformers allow FCVs to be fueled with fuels that are relatively conventional compared to pure hydrogen, they present disadvantages. In particular, reformers are relatively complex, bulky and add weight to the vehicle. Furthermore, a by-product of the reforming process is carbon dioxide, which is widely considered to be a major contributor to global warming.
Therefore, efforts have been made to develop hydrogen fueling stations that supply pure hydrogen directly to a vehicle, thereby removing the need for the vehicle to have an on-board reformer. Experimental hydrogen fueling stations have been built as proof-of-concept demonstrations. Ideas proposed for such fueling stations include installing a reformer in the station to enable the station to receive readily-transportable alcohol or specially formulated petroleum fuels, which are then converted by the reformer into hydrogen, and stored in hydrogen storage tanks for later delivery to the vehicle. Other proposals include fueling stations with electrolyzers that convert supply water into hydrogen fuel and oxygen byproduct.
Experimental hydrogen fueling stations that have been built so far have been complex and must be operated under careful supervision. Even as fueling station technology becomes more refined, unique considerations must be given to their operation that do not exist for conventional petroleum-based fueling stations. For example, special considerations must be given to safely handle and store hydrogen and to house complex equipment like reformers, electrolyzers or high-pressure hydrogen storage tanks in a way that is safe to, and away from the public.
In order for FCVs and other hydrogen-powered vehicles to gain mass acceptance, it is desirable to provide a fueling infrastructure with hydrogen fueling stations that are readily accessible by the FCV-driving public, and in particular, that comply with regulations for safely handling and storing hydrogen in publicly accessible areas.
According to one aspect of the invention, there is provided a hydrogen fueling station comprising: an enclosure having an external air inlet and a ventilation air outlet; a plurality of hydrogen storage tanks located within the enclosure; process components located within the enclosure and in fluid communication with the tanks, for supplying and dispensing pressurized hydrogen gas to and from the tanks; an electrical component housing located within the enclosure, and comprising a pressurization air inlet; a controller housed within the electrical component housing and communicative with the process components, for controlling the supplying and dispensing of hydrogen gas to and from the tanks; and a ventilation assembly. The ventilation assembly comprises: a ventilation air flow path extending from the external air inlet to the ventilation air outlet, the tanks and process components being located within the ventilation air flow path; and a fan located in the air flow path near the external air inlet and upstream of the tanks and process components, and operable to direct air through the air flow path at a rate that maintains the leaked hydrogen concentration in the air flow path below a selected threshold, and to direct air through the pressurization air inlet such that an above-ambient air pressure is maintained inside the electrical component housing.
The enclosure may be substantially vertically elongate. The external air inlet may be located near the base of the enclosure, and the ventilation air outlet may be located at the top of the enclosure. Also, the tanks may be elongated and positioned on end inside the enclosure.
The fueling station may further comprise a tank housing mounted within the enclosure and housing the tanks; the tank housing may comprise a ventilation inlet and outlet in fluid communication with the ventilation air flow path.
The process components may be located substantially beneath the tanks, and may include pneumatic valves and a pneumatic compressor that is pneumatically connected to the pneumatic valves. The pneumatic valves and compressor are both located in the air flow path. The pneumatic valves are in electrical communication with the controller and in hydrogen communication with the tanks. The process components may also include an electrolyzer; the electrolyzer is in electrical communication with the controller and has a hydrogen product outlet in hydrogen communication with the tanks, an oxygen product outlet, and a water supply inlet communicable with a water supply. The oxygen product outlet may be in air communication with the air flow path. The process components may also include a charge port capable of coupling to a hydrogen supply source, supply piping in hydrogen communication with the charge port and at least one tank, and a hydrogen charge compressor in electrical communication with the controller and in hydrogen communication with the supply piping upstream of the tank and downstream of the charge port. The process components may also include a cascade compressor in electrical communication with the controller, and cascade piping in hydrogen communication with the cascade compressor and the tanks.
The fueling station may further comprise a process component housing located within the enclosure below the tanks, and housing the process components. The process component housing comprises a ventilation air inlet and outlet in fluid communication with the ventilation flow path.
The electrical component housing may be located beneath the tanks and further comprises an air outlet. The ventilation assembly may further comprise an exhaust duct extending from the electrical component housing air outlet to the enclosure ventilation air outlet.
According to another embodiment of the invention, the fueling station described above may have electrical components that are located within the enclosure in the air flow path, instead in a pressurized electrical component housing.
According to another aspect of the invention, there is provided a hydrogen fueling station having a small footprint, and comprising: a substantially vertically elongate enclosure; a plurality of elongate hydrogen storage tanks located on end within the enclosure; process components located within the enclosure substantially beneath the tanks and in hydrogen communication with the tanks, for supplying and dispensing pressurized hydrogen gas to and from the tanks; and electrical components located within the enclosure substantially beneath the tanks and including a controller communicative with the process components, for controlling the supplying and dispensing of hydrogen gas to and from the tanks.